A Single Hydrogen Bond Unit Modulates the Dynamics and Cellular Interactions of Fibrous Materials Formed by...

Self-assembling fibrous materials exhibit tunable properties and adaptive responsiveness derived from dynamic self-assembly behavior, making them attractive platforms for biofunctional supramolecular materials. Despite the recognized importance of dynamic behavior in self-assembling systems, the relationship between dynamics and cellular interactions remains poorly understood. Herein, we investigated this relationship using peptide amphiphiles (PAs) as model fiber-forming self-assembling molecules. By modifying hydrogen-bond-forming units at the peptide N-terminus or within the alkyl domain, we tuned the dynamics and intermolecular interactions of PA assemblies without altering their fibrous morphology. Replacement of the N-terminal amide group with a urea group decreased the dynamics of the assemblies through enhanced intermolecular hydrogen bonding and π-π stacking interactions, whereas introduction of an additional amide group in the alkyl chain increased dynamics. These changes in dynamics influence interactions with cell membranes and subsequent cellular uptake. PAs containing urea groups exhibited strong membrane affinity and efficient cellular uptake, while more dynamic assemblies showed reduced uptake. These findings highlight the dynamics of self-assembling materials as an important design parameter for controlling cellular interactions and cellular internalization, offering a new strategy for the rational design of self-assembling materials for drug delivery applications.